This is great! I love projects like this! I have a hobby of making toy programming languages. (Not arguing that's what yours is.) I once made a compiler, but lately I'm satisfied with making interpreters. Executable asts with moderate rearranging capabilities. It is an addictive thing. It started when I wrote a query language for my graph database server back in 2006. I didn't know about property graphs when I started, but that's what it ended up being, and I had to make a query language for it. (I wanted to call it AQL for "associative query language" but turns out that acronym was already taken. I can't remember by what.) I learned how to do it from the dragon book -- cuz I'm old. Anyway, you struck a chord with me. Making a syntax highlighter that's able to resume on errors is an interesting challenge that teaches you a lot about both sides, the front end and the back end.